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%I #23 Dec 17 2016 17:52:43
%S 1,1,1,65,1,217,1,577,730,1001,1,2009,1,2745,3376,4673,1,6778,1,9065,
%T 9262,10649,1,16345,15626,17577,20413,24761,1,31592,1,37441,35938,
%U 39305,42876,55226,1,54873,59320,73577,1,86310,1,95897,95230,97337,1,131033,117650,141626,132652,158249,1,183925,166376
%N Sum of cubes of nonprime divisors of n.
%C a(n) = 1 when n = 1 or n is prime.
%C a(p^k) = (p^(3*k+3) - 1)/(p^3 - 1) - p^3 for p is prime.
%H <a href="/index/Su#sums_of_divisors">Index entries for sequences related to sums of divisors</a>
%F a(n) = A001158(n) - A005064(n).
%e a(4) = 65 because 4 has 2 nonprime divisors {1,4} and 1^3 + 4^3 = 65.
%t Table[DivisorSum[n, #1^3 & , !PrimeQ[#1] & ], {n, 55}]
%t Table[DivisorSigma[3, n] - DivisorSum[n, #1^3 & , PrimeQ[#1] & ], {n, 55}]
%Y Cf. A001158, A005064, A023890, A189120.
%K nonn,easy
%O 1,4
%A _Ilya Gutkovskiy_, Dec 12 2016
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